Homing test

1. Set the C3835/ARC54 to 50 MHz

as shown in figure 3, perform the following test.

and the function selector to HOME, the squelch

Using a 30 MHz signal modulated 10 kHz at

switch to CARR. Adjust the signal generator for

1000 Hz set the signal generator output level for

zero output at 50 MHz. Set the two adjustable

zero output. Adjust the "SQ-ADJ" control for

attenuators to 6 db. Increase the signal generator

minimum sensitivity (fully clockwise) and slowly

output until a "flag down" condition is observed

increase the signal generator output level until

on the Indicator ID48. The signal level required

the receiver is unsquelched. The receiver shall

for "flag down" condition shall not exceed 4.8

unsquelch between 1.0 uv and 6.0 uv. Set the

microvolt.

signal generator output level for zero output. Ad-

just the "SQ-ADJ" control for maximum sensi-

2. Set the signal generator attenuator to

tivity (fully counterclockwise). Under this condi-

50 MHz and the RF ATTENUATOR to 120 micro-

tion, the receiver shall be unsquelched as indi-

volt and unbalance the adjustable pads by 1.0

cated by the presence of background noise, at the

db. Fine tune the signal generator for a maximum

audio output terminals. The receiver shall be con-

deflection of the vertical needle. Re-balance the

sidered squelched when the audio output is 30 db

attenuators to 6.0 db each. The needle shall be

(0.078 volts) below the 41.6 milliwatt (250 Vrms)

centered or within 1.2 dot width either side of

level across the volume control when adjusted for

center or plus or minus 10 microamps. If not,

full volume. Readjust the squelch potentiometer

adjust R227 on the homer needle to center the

on the receiver-transmitter front panel for a 1

needle. The limits for homing zero inclination

microvolt reading on the signal generator.

shall be 0.0 plus or minus 10 microamps. This re-

(d) Tone squelch test. (This test shall be

quirement shall also be met at one frequency in

conducted only when the "TONE" mode of opera-

each of the following ranges: 30.00 MHz to 33.95

MHz and 67.00 MHz to 69.95 MHz. Any readjust-

tion is specified.) Under standard conditions of

ment of R227 at other than 50 MHz shall be re-

(1) above and with the test set up as shown in

checked at 50 MHz for a compromise reading.

figure 4, perform the following tests:

1. Set the signal generator OPERATION

3. With an input of 120 microvolt from

switch to EXT MOD, and RF ATTENUATOR

the signal generator set the left pad at 3 db and

MICROVOLTS to minimum.

the right pad at 6 db, the course indicator shall

2. Set the audio oscillator output level

deflect to the left. Set the left pad at 6 db and

the right pad at 3 db, the course indicator shall

control for reading on the signal generator DE-

deflect to the right. The vertical needle deflection

VIATION meter of 3 kHz.

shall be between the first and second dots on the

3. Slowly increase setting of the signal

horizontal scale of the ID48 indicator or 138

generator RF ATTENUATOR MICROVOLTS

microampere 10 percent. If necessary, adjust

(maintain redline adjustment of RF SET TO

R224 to obtain the desired deflection.

LINE adjust) until the receiver is unsquelched,

at an input of 1.2 microvolt or less.

4. Set the two adjustable attenuators to

6 db and verify that the needle is centered within

4. Set the signal generator RF ATTEN-

dot, if the needle is not within dot adjust

UATOR MICROVOLTS to 120, adjust for 2.5

R-227 for center.

kHz deviation, and set the audio oscillator main

5. Set one adjustable attenuator to 3 db

tuning dial to 145 Hz. Set the signal generator

and the other attenuator to 6 db. Under this con-

OPERATION switch to MOD OFF and note that

dition and for all values a signal input level of 12

receiver squelches as indicated by a sharp de-

microvolt to 10,000 microvolt from the signal

crease in reading on the VTVM. Set the signal

generator, the vertical needle shall deflect at least

g e n e r a t o r OPEPATION switch to EXT MOD

to the wing tip of the ID48 indicator or at least

and verify that the receiver unsquelches. The re-

90 microampere on the horizontal scale, Change

ceiver shall squelch with the modulation off and

the attenuator settings from 3 db to 6 db and 6 db

unsquelch with the modulation on.

to 3 db respectively. The vertical needle deflection

5. Set the audio oscillator main tuning

shall be in the opposite direction. This require-

dial to 155 Hz (maintain 2.5 kHz deviation and

ment shall also be met at one frequency in each

note the same results as in 4 above).

of the following ranges: 30.00 MHz to 33.95 MHz

(e) Homing test. (These tests are to be per-

and 67.00 MHz to 69.95 MHz.

formed with the signal generator modulation

NOTE

"OFF"). Under standard conditions of (1) above

When Indicator ID1351A is used and

and using the test set up as in figure 5, perform

correct response to left and right indica-

the following tests: